1. Field of the Invention
The present invention relates to image capture units and to the forming of such units.
Such units are particularly well adapted to portable equipment such as cell phones, laptop computers, or video cameras.
2. Discussion of the Related Art
FIG. 1 illustrates an image capture unit according to prior art. An integrated circuit chip 1 comprises an image sensor 2 at its surface. The chip is glued on a printed circuit 3 and is electrically connected to this printed circuit by conductive wires. A wall 4 surrounds the package beyond the chip contour. This wall is made of molded resin. A lens 5 rests on the upper surface of the wall. The wall height is adjusted, by means not shown, so that the focal plane of the lens is at the level of the image sensor.
The assembly thus obtained forms an image capture unit welded on a printed circuit 3. The lens is capable of focusing the image of an external illuminated object on the integrated circuit chip.
The forming of such a unit requires multiple operations such as the assembly of the integrated circuit on the printed circuit, the molding of the wall, the gluing of the lens, the adjusting of the distance from the lens to the integrated circuit chip.
The reliability of the assembly depends on the quality of the mounting of the integrated circuit on the printed circuit, and on the quality of the mounting of the lens above the package.
The distance from the lens to the integrated circuit chip should be of a few millimeters with an accuracy of 10 micrometers, which accuracy requires a specific adjustment on each unit.
The surface area taken up by the image capture unit is much larger than the chip surface area.
The functional electrical testing of the image capture unit is performed after the integrated circuit has been separated and assembled on printed circuit 3.